package demo1;
import java.util.LinkedList;
import java.util.Queue;
public class TextMyStack {
    /**
     * 使用2个队列 来 实现栈
     */
    class MyStack {

        private Queue<Integer> qu1;
        private Queue<Integer> qu2;

        public MyStack() {
            qu1 = new LinkedList<>();
            qu2 = new LinkedList<>();
        }

        public void push(int x) {
            if(!qu1.isEmpty()) {
                qu1.offer(x);
            }else if(!qu2.isEmpty()) {
                qu2.offer(x);
            }else {
                qu1.offer(x);
            }
        }

        public int pop() {
            if(empty()) {
                return -1;
            }
            if(!qu1.isEmpty()) {
                int size = qu1.size();
                while(size-1 != 0) {
                    qu2.offer(qu1.poll());
                    size--;
                }
                return qu1.poll();
            }else if(!qu2.isEmpty()) {
                int size = qu2.size();
                while(size-1 != 0) {
                    qu1.offer(qu2.poll());
                    size--;
                }
                return qu2.poll();
            }
            return -1;
        }

        public int top() {
            if(empty()) {
                return -1;
            }
            if(!qu1.isEmpty()) {
                int size = qu1.size();
                int tmp = -1;
                while(size != 0) {
                    tmp = qu1.poll();
                    qu2.offer(tmp);
                    size--;
                }
                return tmp;
            }else if(!qu2.isEmpty()) {
                int size = qu2.size();
                int tmp = -1;
                while(size != 0) {
                    tmp = qu2.poll();
                    size--;
                    qu1.offer(tmp);
                }
                return tmp;
            }
            return -1;
        }

        public boolean empty() {
            return qu1.isEmpty() && qu2.isEmpty();
        }
    }
}
